A backlight is a light source mounted on a back of a Liquid Crystal Display (LCD). A direct type backlight typically includes a light guide plate and a plurality of light-emitting diodes (LEDs) positioned on a first surface of the light guide plate and arranged in a matrix. The light emitted by the LEDs is transmitted through the light guide plate.
In order for making light emitted by a direct type backlight an uniform light, light emitting sides of LEDs may be formed with a certain distance from a light guide plate when the LEDs are placed. Such distance may ensure that light emitted by adjacent LEDs may be mixed to preliminarily homogenize the light before the light enters the light guide plate, and the optical quality of the backlight may be ensured.
As such, for a direct type backlight, it is necessary to allow a certain distance between an LED and a light guide plate. Because of that, the structure of the backlight is limited by the distance between a light emitting unit (e.g., a LED) and the light guide plate. Thus, the ability to flexibly adjust the backlight is relatively lower.